feat(Backend): go test using gh actions

[JavierRibaldelRio]

Configure GitHub actions to execute go's tests before a PR to main or develop.

The order to execute the tests is the following: go test $(go list ./... | grep -v pkg/boards | grep -v pkg/broker/topics/message)

grep -v instructions excludes the directories pkg/boards and pkg/broker/topics/message

While pkg/boards is excluded because returns BLCU-related errors, topic/message returns this.

# github.com/HyperloopUPV-H8/h9-backend/pkg/broker/topics/message
./update.go:137:15: conversion from PacketId (uint16) to string yields a string of one rune, not a string of digits

which is a warning produced by go vet, however during testing produces a compilation error, even though during build it does not.

Ignore the status of previous confirmations because their purpose was to prove the gh action.

Merry Xmas!